Fenyi Jie, a Chinese medicinal material, is the dried rhizome of Dioscorea hypoglauca Palibin, a plant in the family Dioscoreaceae. It is harvested in autumn and winter, and the roots are washed, sliced, and dried.
Fenyi Jie is irregular thin slices, with uneven edges and varying sizes, approximately 0.5mm thick. Some have a brown-black or gray-brown outer skin. The cut surface is yellow-white or light gray-brown, with scattered vascular bundles in a dot-like pattern. The texture is loose and slightly elastic. It has a slight odor and a pungent, slightly bitter taste.
(1) Transverse section of the material:
The outer layer consists of multiple rows of cork cells. The cortex is narrow, with elongated cells that are slightly thickened and have visible pits. Mucilage cells are scattered, containing bundles of calcium oxalate crystals. The central column contains a limited number of external collateral and almost concentric vascular bundles. Thin-walled cells have slightly thickened walls, with pits and starch grains.
The powder of the material is yellow-white. Starch grains are single, round, oval, or elongated, with a diameter of 5-32μm and up to 40μm in length, with a point-like or fissure-like hilum. Compound grains are few and mostly composed of two subgrains.
There are numerous thick-walled cells with lignified walls and obvious pits, some resembling stone cells, polygonal, fusiform, or elongated rectangular, with a diameter of 40-80μm and up to 224μm in length. Bundles of calcium oxalate crystals are 64-84μm long.
(2) Take 10g of the powder, add 100ml of water, soak overnight, heat in a 60°C water bath for 10 minutes, filter while hot, take 2ml of the filtrate and divide it into two test tubes. Add 2ml of sodium hydroxide solution to one tube and 2ml of hydrochloric acid solution (1:20) to the other tube, close tightly, shake vigorously for 1 minute. The foam in the alkaline solution tube is several times higher than that in the acid solution tube.
Fenyi Jie should be stored in a well-ventilated and dry place.
